Application Of Fluorescent Peptide Nanomaterials In Enzyme Electrochemical Biosensors

Enzyme electrochemical biosensor is a widely used biosensor,which can detect various indicators such as glucose,lactic acid,hydrogen peroxide and so on by immobilizing different enzyme molecules.One of the important factors affecting the performance of enzyme electrochemical biosensors is the modification process of electrodes.Nanomaterials are widely used to modify enzyme electrodes due to their good properties to improve enzyme activity and achieve sensor signal enhancement.At present,the materials commonly used for electrode modification include metal and metal oxide nanomaterials,carbon nanomaterials,dielectric nanomaterials,and polymer nanomaterials.With the continuous in-depth research on enzyme electrochemical biosensors,sensors have gradually developed towards miniaturization,intelligence and integration,and have shown a wide range of application prospects in the fields of disease diagnosis and biological detection.Biological toxicity and biological safety have higher requirements.At present,the commonly used electrode modification materials generally have the problem of biological toxicity,which limits their application in the field of life sciences.Peptide nanomaterials have received extensive attention because of their superior biocompatibility and degradability.Polypeptide nanomaterials with fluorescent properties have the advantages of good biological safety,high biological activity and good electrochemical properties.In this thesis,fluorescent peptides are used as the material of the modified electrode to construct an enzyme electrochemical biosensor with good biocompatibility and signal amplification function,so as to improve the performance of the sensor.The specific research content is as follows:1.The WF dipeptide fluorescent nanoparticles（WF-DNPs）with good morphology and optical properties were prepared by the chelation of WF dipeptide and Zn²⁺,The effects of temperature and Zn²⁺concentration on the fluorescence properties and structural morphology of WF-DNPs were also studied.The fluorescence quenching experiments of WF-DNPs by graphene oxide and gold nanorods respectively verified the electron transfer ability of WF-DNPs,indicating that WF-DNPs have good electrochemical properties.2.Use WF-DNPs and horseradish peroxidase（HRP）to construct an electrochemical biosensor with GCE/WF-DNPs/HRP/NF as the working electrode,The detection performance of GCE/WF-DNPs/HRP/NF electrochemical biosensor for H₂O₂was studied by cyclic voltammetry.The results show that WF-DNPs can amplify the signal of the sensor,and the constructed sensor has good signal response,repeatability and selectivity to hydrogen peroxide,which proves that WF-DNPs and HRP form a stable complex on the electrode surface and have stable electrochemical activity.3.In order to further study whether other polypeptide nanomaterials with fluorescent properties have similar properties,an electrochemical biosensor was constructed by using c-SF and c-SY to assemble nanofibers with fluorescent properties together with peroxidase.The detection performance of the electrochemical biosensor for H₂O₂ was studied by cyclic voltammetry.It is found that c-SF has a certain electrochemical signal amplification function for the sensor,while c-SY does not have this characteristic.